Once a user equipment (UE) connects to an Long Term Evolution (LTE) mobile communication network a default bearer is assigned, which remains as long as the UE is connected to the LTE mobile communication network. The UE can have additional default bearers as well. Each default bearer comes with a separate IP address. Usually default bearers provide best effort service, which means that the quality and transmission speed of the connection may depend on the network load and/or time of the day. The default bearer has a non-Guaranteed Bit Rate (non-GBR).
A dedicated bearer can be created on top of a default bearer to provide a dedicated tunnel to one or more specific data traffic (i.e. VoIP, video, etc.). The dedicated bearer uses the IP address of the default bearer and therefore does not occupy an additional IP address. Dedicated bearers mostly provide a Guaranteed Bit Rate (GBR), but can also provide non-GBR service. The GBR per dedicated bearer can be specified individually for uplink and downlink. The transmission resources for a GBR dedicated bearer are reserved and blocked by an admission control function. However, it is possible that multiple applications share a dedicated bearer and thus, the GBR of the dedicated bearer will be used by multiple applications and it is not guaranteed that every application can use the GBR of the dedicated bearer.
Further, a Quality of Service (QoS) Class Indicator (QCI) can be assigned to either a default bearer or a dedicated bearer. The QCI specifies the treatment respectively handling, like e.g. scheduling weight, admission thresholds, queue management thresholds, link-layer protocol configuration, etc. of the traffic send over the bearer between the UE and the LTE mobile communication network. The QCI specification with corresponding parameters and common applications are shown in the following table, as defined in the 3GPP TS 23.203 standard “Policy and Charging Control Architecture”:
ResourcePacket delayPacket errorExampleQCItypePrioritybudgetloss rateApplication1GBR2100 ms1e−2ConversationalVoice2GBR4150 ms1e−3ConversationalVideo3GBR3 50 ms1e−3Gaming4GBR5300 ms1e−6Non-conversationalvideo5non-GBR1100 ms1e−6IMS signaling6non-GBR6300 ms1e−6Video, www,email, ftp7non-GBR7100 ms1e−3Interactivegaming8non-GBR8300 ms1e−6Video, www,email, ftp9non-GBR9300 ms1e−6Video, www,email, ftp
However, the QCI assigned to a bearer between the UE and the LTE mobile communication network is the same for the uplink and downlink data transmission. In case an application of the UE requires specific Quality of Service (QoS) characteristics for one direction of the bearer to be set up, the same resources would also be reserved for the other direction, even if not needed. Although examples are given for each QCI, the data transmission between the UE and the EPC is unaware of the application or application type transmitting the data.